1. Field of the Invention
The present invention relates to an image capturing apparatus such as a digital camera, an image processing apparatus, and an image processing method and, more particularly, to an image processing technique of processing an image obtained by photographing when a movement occurs at the time of the photographing.
2. Description of the Background Art
An image capturing apparatus such as a digital camera having a movement correcting mechanism (auto stabilization mechanism) for mechanically correcting a movement (for example, blur) of the image capturing apparatus relative to the subject, which occurs during photographing is known. The movement correction of this kind is realized by detecting a movement amount by using an acceleration sensor or the like and, for example, by displacing an optical system or an image capturing device such as a CCD image sensor to correct a relative displacement between the image capturing apparatus and the subject in accordance with the movement amount.
However, the configuration and control of such a mechanical movement correcting mechanism are complicated. Moreover, since response speed to a movement is limited, when a relative displacement between the image capturing device and the subject due to a movement occurs at a speed higher than the response speed, a situation such that a movement cannot be corrected by the mechanical movement correcting mechanism occurs. Therefore, attempts are being made to correct a movement without providing the mechanical movement correcting mechanism.
As a technique for correcting a movement without providing a movement correcting mechanism, for example, an image capturing apparatus for detecting a movement amount during exposure of an image capturing device, if the movement amount exceeds a predetermined value during the exposure, interrupting the exposure and compensating deterioration in picture quality due to insufficient exposure by increasing the gain of an amplifier provided at the post stage of the image capturing device is known (for example, Japanese Patent Application Laid-Open No. 2001-45361).
In the conventional technique, however, when the exposure amount is insufficient, the gain is increased uniformly for a whole image, so that a noise component is also amplified. It causes a problem such that an image of low picture quality with conspicuous noise is resulted.